Abstract

Murine blood plasma rapidly inactivates nitrosamides and nitrosocarbamates but not nitrosoureas. The mechanism of this inactivation in murine blood plasma has been investigated. The vast majority of activity (>97%) was inhibited by serine hydroxylase inhibitors. Also, 92% of the activity was inhibited by bis(p-nitrophenyl)phosphate, a selective inhibitor of carboxylesterases. Decomposition products formed after blood plasma action on N-ethyl-N-nitrosoacetamide or N-methyl-N-nitrosoethylcarbamate were separated and identified by gas chromatography. The products formed were consistent with a hydrolytic cleavage of the amidic bond. These observations are consistent with the idea that the major active factor(s) in plasma is a carboxylesterase(s).

Footnotes

↵1 This is Contribution 1266 from the Department of Biology, The Johns Hopkins University.

↵2 Recipient of Grant 5-R01-CA16783 from the National Cancer Institute. To whom requests for reprints should be addressed.